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The main goal of this article is to consider the fixed time control problem of perturbed chaotic systems by virtue of sliding mode control. For this aim, this article presents a novel fixed time stability theorem at first by the Lyapunov tools. Then combining the obtained stability theorem and sliding mode technique, a new sliding mode surface is constructed and some novel controllers are designed appropriately to stabilize the discussed chaotic system. The proposed controllers have two main advantages: (1) The control criteria is robust against the effects of perturbations. (2) The convergence time, which is only dependent on the control parameters regardless of the initial conditions, is bounded by a fixed constant. Finally two typical systems are taken as the numerical examples to verify the validity of the control strategy.
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http://dx.doi.org/10.1016/j.isatra.2021.02.012 | DOI Listing |
ISA Trans
September 2025
School of Automation, Northwestern Polytechnical University,1 Dongxiang Road, Chang'an District, Xi'an, Shaanxi 710129, PR China. Electronic address:
A novel practical predefined-time sliding mode control strategy is proposed for the flight formation of a small tandem-rotor wheeled UAV (TRW-UAV) with unknown upper bound external disturbances and uncertainties in this paper. Firstly, a new predefined-time sliding mode surface is proposed to guide all errors of the position and velocity loops to converge to the origin in a predefined-time. Furthermore, a dynamic surface control approach is utilized to circumvent the higher-order differentiation when controlling the actuator loop.
View Article and Find Full Text PDFLangmuir
September 2025
ThAMeS Multiphase, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, U.K.
The evaporation of surfactant-laden sessile droplets has widespread applications in both natural and technological contexts. This study explores the evaporation of droplets containing a nonionic surfactant (tristyrylphenol ethoxylates (EOT)), an anionic surfactant (sodium benzenesulfonate with alkyl chain lengths of C-C (NaDDBS)), and their mixtures at / mole ratios of 0.01, 0.
View Article and Find Full Text PDFUltrasonics
September 2025
Paderborn University, Paderborn, Germany.
This study investigates the phenomenon of mode repulsion in Lamb waves propagating through two coupled plates with an elastic interface. Using a spring-based coupling model and the Scaled Boundary Finite Element Method, the dispersion curves of the coupled system are analyzed under various interface conditions-weak coupling, sliding boundary, and perfect coupling. This research highlights how the mechanical stiffness of the interface influences the separation of modes and the emergence of repulsion regions.
View Article and Find Full Text PDFMod Pathol
September 2025
School of Population Medicine and Public Health, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China. Electronic address:
Deep learning (DL) has significantly improved the diagnostic accuracy and efficiency of cytopathologists. However, current DL-assisted reading modes have yet to be fully evaluated, and there is limited evidence regarding cytopathologists' preferences and experiences. This study employs a randomized, controlled, four-way crossover design to assess the effectiveness of four different reading modes in cervical cytopathology readings.
View Article and Find Full Text PDFISA Trans
August 2025
College of Electrical Engineering, Sichuan University, Chengdu, 610065, China. Electronic address:
In this study, the problem of trajectory tracking optimal control of robotic manipulator system subjected to external load disturbances is investigated, and an observer-based discrete fast terminal sliding mode predictive optimal control (FTSMPC) strategy is presented. Firstly, to address the unknown friction torque and load disturbances, a novel discrete-time extended state observer is designed to estimate the lumped disturbances, in which the boundedness of the observation error can be guaranteed through theoretical analysis. Then, with the outputs of the observer, an FTSMPC control approach is designed.
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